Some types of Power Amplifiers (PAs) utilize power transistors that operate as switches, e.g., in Class D, E or F. The input signal is provided to such amplifiers as a series of pulses that cause the transistors to switch rapidly between conduction and cutoff. Pas of this sort are sometimes referred to as Digital PAs (PAs).
The description above is presented as a general overview of related art in this field and should not be construed as an admission that any of the information it contains constitutes prior art against the present patent application.